Almost every evening a couple of officers stand at the end of my street in Tokyo. There they can easily catch motorists making an illegal right turn. The rule exists only at certain times of day making it very hard for motorists to comply.
The police know this and just wait there like a bear fishing for spawning salmon.
It seems so pointless. If the right turn is really a problem then mark it in such a way as to make compliance obvious. If not, then just allow it and stop enforcement.